Numerical simulations of water surfaces for improved
evaporation prediction

Abstract

Water is normally stored in open reservoirs such as dams. A key consideration and challenge that water resource managers are currently facing for improved water management is the evaporation rate in such storage facilities. The impacts that the changing climate has on communities currently and into the future will prove a considerable task for water resource managers to meet the demands for a national population which is growing at a fast pace. Being able to satisfactorily quantify the rate of evaporation from open water storage reservoirs within Australia will enable the correct implementation of measures to mitigate losses that are expected in the coming decades due to a rising climate, estimated changes in precipitation rates andcurrently experienced changes in wind patterns. Not only is the increased pressure on the distribution of water to maintain public health but agricultural practices anda large number of other varied industries are also suffering.

The consequential effects of evaporation losses are numerous and may prove to be linked to decreased productivity and efficiencies within many sectors of industry. This brings the value of maintaining important and valuable water supplies to the top of the list for many industrial sectors. This has increased the need for furtherunderstanding to be gained via research into the effects and prevention of losing so much of a precious resource every year.

Currently, research is being undertaken at the National Centre for Engineering in Agriculture (NCEA) at the University of Southern Queensland that investigates methods of reducing the evaporation rate in a cost-effective fashion. Recent findings suggest that the aqueous thermal boundary layer is a key component contributing to the evaporation rate. This is the small region close to the surface of the water where temperature gradients are important.

It the intended purpose of this dissertation to provide insight into current research whilst also adding new research that provides results by performing simulations ofthe thermal boundary layer. This is in order to characterise the conditions under which the temperature gradient promotes or retards evaporation.